/* RFC 019 §7 FFI canary: an honest unprobed C frame with a 96 KiB local,
 * touched from its LOW end first — the exact "one sub rsp steps over a small
 * guard" pattern the RFC's motivating incident hit (a cargo-vendored gz
 * build; cc-invoked builds do not enable -fstack-clash-protection, and this
 * file pins that off explicitly so the canary stays a canary even on
 * hardened-default toolchains). */
void smarm_canary_burn(void) {
    volatile char buf[96 * 1024];
    buf[0] = 1; /* deepest address first */
    for (unsigned i = 0; i < sizeof buf; i += 4096) {
        buf[i] = (char)i;
    }
    buf[sizeof buf - 1] = 1;
}